Electro-optical holographic display

• US 5,581,378 A
• Filed: 02/01/1993
• Issued: 12/03/1996
• Est. Priority Date: 02/01/1993
• Status: Expired due to Term

• Current Assignee: University of Alabama in Huntsville (University of Alabama System)
• Original Assignee: Board of Trustees of The University of Illinois
• Inventors: Kowel, Stephen T., Kulick, Jeffrey H.
• Primary Examiner(s): Dzierzynski, Paul M.
• Assistant Examiner(s): Juba, Jr., John
• Application Number:
  US08/011,782
• Time in Patent Office: 1,401 Days
• Field of Search: 359/9, 359/22, 359/23, 345/205, 345/206, 345/102, 345/4, 345/5, 345/6, 345/207, 345/903, 358/2, 358/59, 348/40, 348/383, 364/525
• US Class Current: 359/9
• CPC Class Codes: G02F 1/136277 formed on a semiconductor substrate, e.g. of silicon
• CPC Class Codes: G02F 1/292 by controlled diffraction or phased-array beam steering controlled diffraction for optical switching G02F1/31
• CPC Class Codes: G03H 1/08 Synthesising holograms, i.e. holograms synthesized from objects or objects from hologramsusing electric digital computers G06F; G06T
• CPC Class Codes: G03H 1/26 Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
• CPC Class Codes: G03H 2225/23 Grating based SLM
• CPC Class Codes: G09G 3/003 to produce spatial visual effects
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: Y10S 345/903 Modular display
• CPC Class Codes: Y10S 359/90 Methods

Abstract

A display device which is capable of producing a plurality of different views of an image simultaneously is provided. The display includes an array of semiconductor devices with an electro-optical material disposed over the array of semiconductor devices. The semiconductor devices include electrodes which are selectively activated to form refraction gratings in the electro-optical material. Each of the semiconductor devices also includes a processor layer which can determine a refraction grating which is necessary for generating a predetermined number of discrete images which are visible from a predetermined number of different vantage points or viewer positions. Since a different image is provided to each eye, the viewer is provided with a perception of depth such that a three-dimensional image is provided. In addition, since different images or at least different image perspectives are provided to different points, horizontal and/or vertical parallax of the display is attained.

Claims

1. A holographic display apparatus comprising:

a display device;

means for producing a series of two dimensional projections of an object to be rendered for a plane which is coincident with a plane of the display device;

means for producing wavefront interference information, independent of the object data in the series of two dimensional projections of an object, relative to an intermediate plane located at a predetermined position relative to the display device;

means, connected to the means for producing two dimensional projections, the means for producing wavefront interference information, and the display device, for combining said two dimensional projections and said wavefront interference information once the series of two dimensional projections of an object has been produced; and

means, connected to the display device and the means for combining said two dimensional projections and said wavefront interference information, for creating a diffraction grating in said display device based upon a combination of the two dimensional projections and the wavefront interference information to thereby provide a holographic image of an object from a number of positions relative to said display device.

2. An apparatus according to claim 1, wherein said means for producing said two dimensional projections produces said two dimensional projections using a ray tracing operation.

3. An apparatus according to claim 1, wherein said display device includes an electro-optic material and a pair of electrodes disposed in operable contact with said electro-optic material, and wherein said means for creating a diffraction grating in said display device includes:

means for transmitting an electrical signal to the pair of electrodes in response to the combination of the two dimensional projections and the wavefront interference information; and

means for creating a diffraction grating within the electro-optic material of said display device in response to said transmitted electrical signal.

4. An image display device having a multilayer structure, comprising:

a processor layer including means, responsive to a series of two dimensional projections of an object and to wavefront interference information which is independent of the object data in the series of two dimensional projections of said object, for combining the two dimensional projections and the wavefront interference information once the series of two dimensional projections is provided thereto, said processor layer also including driving transistors for generating respective driving signals based upon the combination of the two dimensional projections and the wavefront interference information;

an electro-optic material layer; and

a plurality of layers disposed between said processor layer and said electro-optic material layer having through holes with connectors passing therethrough operably connecting the driving transistors of the processor layer to the electro-optic material layer such that the driving signals of the driving transistors create a diffraction grating within said electro-optic material layer based upon a combination of the two dimensional projections and the wavefront interference information to thereby provide a holographic image of an object from a number of positions relative to said electro-optic material layer.

5. A device according to claim 4, wherein said electro-optic material layer includes three different color filters for generating a color holographic image and the electro-optic material layer displays three different gratings, corresponding to the three different color filters.

6. A device according to claim 4, wherein power is supplied to said processor layer via through holes in a bottom portion of said processor layer.

7. A device according to claim 4, wherein power is supplied to said processor layer via power rails mounted on a transparent layer disposed on top of the electro-optic material layer.

8. A device according to claim 4 further comprising means, operably connected to said processor layer, for optically receiving data related to the series of two dimensional projections of an object.

9. A device according to claim 4 wherein said plurality of layers disposed between said processor layer and said electro-optic material layer comprises a first optical interface layer which includes at least one electrode for electrically connecting a respective driving transistor of said processor layer to said electro-optic material layer.

10. A device according to claim 9 wherein said first optical interface layer comprises a plurality of transparent electrodes for electrically connecting respective ones of the driving transistors of said processor layer to said electro-optic material layer.

11. A device according to claim 9 wherein said plurality of layers disposed between said processor layer and said electro-optic material layer further comprises a second optical interface layer which includes at least one electrode, disposed in an orthogonal relation to the at least one electrode of said first optical interface layer, for electrically connecting a respective driving transistor of said processor layer to said electro-optic material layer.

12. An image display apparatus including:

an array of very large scale integration (VLSI) semiconductor devices, each of said plurality of VLSI semiconductor devices including;

a transparent cover layer;

a second layer having electrodes thereon;

a layer of electro-optic material disposed between said transparent cover layer and said second layer;

a processor layer which includes drive electronics for creating driving signals which are applied to said electro-optic layer, and processing electronics, responsive to a series of two dimensional projections of an object and to wavefront interference information which is independent of the object data in the series of two dimensional projections of said object, for combining the two dimensional projections and the wavefront interference information once the series of two dimensional projections is provided thereto, said drive electronics responsive to said processing electronics for creating driving signals which create a diffraction grating in said electro-optic layer to thereby provide a holographic image of an object from a number of positions relative to said electro-optic material layer;

wherein said electrodes of each of said VLSI devices supply signals to said electro-optic material thereof such that each of said electrodes has a corresponding through hole in the second layer and each of said electrodes faces outwardly towards a viewer of the device.

13. An apparatus according to claim 12, wherein the diffraction grating created in said electro-optic material of each of said VLSI devices include interference patterns which generate a holographic image.

14. An apparatus according to claim 12, wherein the electrodes contacting the electro-optic material of each of said VLSI devices are arranged in a plane which is parallel to a plane of said transparent cover layer wherein two of said electrodes apply an electric field through the electro-optic material, said electric field beginning at one of said two electrodes and ending at the other of said two electrodes.

15. An apparatus according to claim 12, wherein the processing layer of each of said VLSI devices provides said signals to the electrodes such that said display provides both horizontal and vertical parallax.

16. An apparatus according to claim 12, wherein the drive electronics of each of said VLSI devices include a plurality of shift registers and a plurality of drive transistors, and wherein said shift registers store image information and provide signals to the drive transistors for supplying voltages to said electro-optic material layer.

17. A device for rendering a holographic image, comprising:

a display device;

means for producing a series of two dimensional projections of an object to be rendered for a plane which is coincident with a plane of the display device;

means for producing wavefront interference information, independent of the object data in the series of two dimensional projections of an object, relative to an intermediate plane located at a predetermined position relative to the display device;

means, connected to the means for producing two dimensional projections, the means for producing wavefront interference information, and the display device, for combining said two dimensional projections and said wavefront interference information once the series of two dimensional projections of an object has been produced; and

means, connected to the display device and the means for combining said two dimensional projections and said wavefront interference information, for creating a diffraction grating in said display device based upon a combination of the two dimensional projections and the wavefront interference information to thereby provide a holographic image of an object from a number of positions relative to said display device;

wherein said means for creating a diffraction grating includes;

means for generating an electrical signal based upon a combination of the two dimensional projections and the wavefront interference information;

means for applying the generated electrical signal to a drive transistor located in a first layer of a multilayer display module;

means for producing a drive signal by said drive transistor in response to the generated electrical signal;

means for transmitting said drive signal through at least a second layer of said multilayer display module to a third layer of said multilayer display module which is an electrical contact layer;

means for transmitting said drive signal from said third layer to an electrode connected to a fourth layer which is an electro-optic layer; and

means for creating the diffraction grating in said electro-optic layer in response to said drive signal transmitted from said fourth layer.